Methodological issues in behavioral immunology research with humans

This paper summarizes important methodological issues that are particularly relevant for behavioral immunology research with humans. The assessment of such salient parameters as nutrition, drug/alcohol use, physical activity, and health are discussed. In addition, a number of logistical issues are addressed.

Immunological consequences of acute and chronic stressors: mediating role of interpersonal relationships

This review presents recent studies examining the relationship between acute and chronic stressors, changes in immune function, and interpersonal relationships. Data are given which document immunosuppressive effects of commonplace, short-term stressors, as well as more prolonged stressors, such as marital disruption and caregiving for a relative with Alzheimer's disease. Immune changes included both quantitative and qualitative changes in immune cells, including changes in herpes virus latency, decreases in the percentages of T-helper lymphocytes and decreases in the numbers and function of natural killer cells. These effects occurred independently of changes in nutrition. Psychological variables, including loneliness, attachment and depression were related to the immune changes. The data are discussed in a framework in which quality interpersonal relationships may serve to attenuate the adverse immunological changes associated with psychological distress, and may have consequences for disease susceptibility and health.

Phorbol ester and Epstein-Barr virus dependent transformation of normal primary human skin epithelial cells

Substantial evidence has implicated Epstein-Barr virus (EBV) in the aetiology of two human neoplasms, nasopharyngeal carcinoma (NPC) and Burkitt's lymphoma. This is supported by the presence of high antibody titres to EBV early antigen and virus capsid antigen, as well as antibody to two viral-associated enzymes, DNase and DNA polymerase. Patients with NPC, particularly the undifferentiated form, are commonly found to have EBV DNA in the tumour. Ito and others have presented strong epidemiological evidence that phorbol esters are related to the unusual geographic distribution of NPC in southeastern regions of China. There appears to be a close link between the widespread EBV infection of the Asian population and the distinct regional distribution in China of plants that produce diterpene ester. Naturally occurring phorbol esters are produced by plants of the Euphorbiaceae and Thymelaeaceae, which are used as traditional herbal medicines. Although it has been established that EBV can infect epithelial cells isolated from NPC as well as certain normal epithelial cells, there has been no in vitro evidence that EBV induces neoplastic transformation in normal human epithelial cells with or without exposure to phorbol esters. We report here evidence that transformation of normal human epithelial cells results from exposure to infectious EBV and that transformation is dependent on the presence of phorbol esters.

Chronic stress and immunity in family caregivers of Alzheimer's disease victims

Although acute stress has been associated with transient immunosuppression, little is known about the immunologic consequences of chronic stress in humans. In order to investigate possible health-related consequences of a long-term stressor, we obtained blood samples for immunologic and nutritional analyses and psychologic data from 34 family caregivers of Alzheimer's disease (AD) victims and 34 sociodemographically matched comparison subjects. Family caregivers for AD victims were more distressed than comparison subjects without similar responsibilities. Greater impairment in the AD victim was associated with greater distress and loneliness in caregivers. Caregivers had significantly lower percentages of total T lymphocytes and helper T lymphocytes than did comparison subjects, as well as significantly lower helper-suppressor cell ratios; caregivers also had significantly higher antibody titers to Epstein-Barr virus than did comparison subjects, presumably reflecting poorer cellular immune system control of the latent virus in caregivers. The percentages of natural killer cells and suppressor T lymphocytes did not differ significantly. These data suggest that chronically stressed AD family caregivers do not show immunologic or psychologic adaptation to the level of their well-matched age peers.

Stress-related immune suppression: health implications

This study used a year-long prospective design to assess linkages among distress, immunity, and illness. Serial blood samples were collected from 40 first-year medical students at the first, third, and fifth examination periods, as well as 1 month before each. There were significant decrements in the production of gamma-interferon by concanavalin A-stimulated lymphocytes obtained at the time of examinations. Antibody titers to Epstein-Barr virus (EBV) increased during examination periods, suggesting reactivation of latent EBV and therefore poorer cellular immune control of latent virus. We obtained data that suggest that T-cell killing by memory T lymphocytes of EBV transformed autologous B lymphocytes also declined during examination periods. The activity of a lymphokine, leukocyte migration inhibition factor, normally suppressed during recrudescence of herpes simplex virus type 2 infections, was altered during examination periods and an increase in both plasma and intracellular levels of cyclic AMP associated with examination stress was observed. An increase in the incidence of self-reported symptoms of infectious illness was also associated with examination periods. The data support the linkage between stress-related immunosuppression and health.

Norepinephrine and dopamine metabolites and educational variables in boys with attention deficit disorder and hyperactivity

The present study evaluated the biochemical measures of urinary homovanillic acid (HVA) and 3-methoxy-4-hydroxy-phenylglycol (MHPG) in relation to functioning on selected psychoeducational tests in a group of boys with attention deficit disorder and hyperactivity. The Wechsler Intelligence Scale for Children-Revised (WISC-R), the Wide Range Achievement Test (WRAT), and the Peabody Picture Vocabulary Test were administered to 28 hyperactive and 23 control subjects. The findings suggest subtle differences in psychoeducational test performance in relation to specific levels of homovanillic acid and MHPG.

Marital quality, marital disruption, and immune function

Marital disruption is associated with significant increases in a variety of psychologic and physical disorders. In order to examine psychologic and physiologic mediators, self-report data and blood samples were obtained from 38 married women and 38 separated/divorced women. Among married subjects, poorer marital quality was associated with greater depression and a poorer response on three qualitative measures of immune function. Women who had been separated 1 year or less had significantly poorer qualitative and quantitative immune function than their sociodemographically matched married counterparts. Among the separated/divorced cohort, shorter separation periods and greater attachment to the (ex)husband were associated with poorer immune function and greater depression. These data are consistent with epidemiologic evidence linking marital disruption with increased morbidity and mortality.

Electrorotation of lymphocytes--the influence of membrane events and nucleus

Electrorotation--the spin of cells in rotating high frequency electric fields--has been used to investigate properties of human peripheral blood lymphocytes. The rotation spectra of lymphocytes deviate from those of single shell spheres. The deviations are caused by the electrical properties of the nucleus in the cell interior. Electrorotation allows the distinction between successfully stimulated lymphocytes and unstimulated cells after application of concanavalin A. Notwithstanding the fact that only a proportion of the cells will be mitogenically stimulated we detected an enhanced cell membrane conductivity for the whole cell population immediately after the addition of mitogen.

Further evidence for a membrane potential-dependent shape transformation of the human erythrocyte membrane

The influence of various factors (pH, temperature, sodium gluconate) on the ionic strength-dependent stomatocyte-discocyte-echinocyte transformation of the human erythrocyte membrane was investigated. The results give further evidence for a correlation between shape of erythrocyte membrane and the transmembrane potential of the cells.

Stress depresses interferon production by leukocytes concomitant with a decrease in natural killer cell activity

This study addressed the effects of a commonplace stressful event on interferon production and natural killer (NK) cell activity and numbers. The quantity of interferons (IFN) produced by concanavalin A stimulated leukocytes obtained from 40 medical students during examinations was significantly lower when compared with IFN levels produced by peripheral blood leukocytes (PBLs) taken 6 weeks earlier (baseline). In addition, three different assays measuring NK cells also showed significant decrements during examinations when compared with baseline samples. These assays included lysis of MOLT-4 target cells, percentage of anti-Leu-7+ (NK) cells, and percentage of large granular lymphocytes. Self-report data documented the significantly greater distress associated with examinations in comparison with baseline samples. The data have implications for immunosuppressive disorders and stress-associated illnesses.

Electrorotation--a new method for investigating membrane events during thrombocyte activation. Influence of drugs and osmotic pressure

The measurement of the spin of cells in rotating high-frequency electric fields ('electrorotation') make possible the investigation of dielectric membrane properties of single cells. This method was applied to membrane permeability changes accompanying thrombocyte activation and compared with light-scattering data. Describing the dielectric behavior of platelets by a single-shell model and assuming a sufficiently low membrane conductivity of 1 X 10(-7) S/m we found for nonactivated platelets a membrane capacity of 5.5 mF/m2 and the conductivity of the internal medium was estimated to be 0.12 S/m. Upon activation, the electrorotation decreased continuously, with half-times in the range of few minutes. This could be explained assuming a 500-fold increase in membrane conductivity. The application of both local anesthetics and virostatics inhibited the decrease of electrorotation, as did hypertonic osmotic pressure. In all cases this was accompanied by inhibition of platelet aggregation. Hypotonic solutions induced self-aggregation and spontaneous loss of electrorotation. It was concluded that the increase in permeability of the granule membrane is a crucial step in the release reaction and that the electrorotation method is able to detect the incorporation of the granule membranes into the plasma membrane during activation. The advantage of this electrorotation method is that it enables measurements on a single-cell level, thus avoiding interactions between platelets.

Conformation of nefopam hydrochloride, a novel analgesic

The solid state structures of (+/-)- and (+)-nefopam hydrochloride (3,4,5,6-tetrahydro-5-methyl-1-phenyl-1H-2,5-benzoxazocine hydrochloride, 1) were determined by single crystal X-ray diffraction analysis. (+/-)-Nefopam hydrochloride gave crystals belonging to monoclinic P21/c space group, and at 298 K: a = 11.766 (1) A, b = 7.741 (1) A, c = 16.907 (3) A, beta = 97.43 (1) degrees, V = 1527.0 (7) A3, Z = 4, R = 0.0336, and Rw = 0.0452. (+)-Nefopam hydrochloride monohydrate gave crystals of the orthorhombic P2(1)2(1)2(1) space group, and at 298 K: a = 9.651 (2) A, b = 19.747 (2) A, c = 8.504 (2) A, V = 1620.7(7) A3, Z = 4, R = 0.0432, and Rw = 0.0690 for the (1S,5S)-model. The diastereoisomer found in the chiral crystal was also found in the solid racemic modification: (1S,5S) in the monohydrate of (+)-1 and (1R,5R)/(1S,5S) in (+/-)-1. 1H and 13C[1H] NMR spectroscopy revealed two distinct, major and minor, N-protonated species in CD2Cl2 solution differing in the stereochemistry of the N-methyl group. The molecular structures of the crystals of (+/-)-1 and (+)-1 X H2O (a) indicate a modified boat-chair conformation of the eight-membered ring with an equatorial N-methyl group, caused by two sp2-hybridized ring atoms, and (b) correspond to the stereochemistry of the minor species in solution.

Heterogeneity of Epstein-Barr virus derived from a nasopharyngeal carcinoma that has transforming and lytic properties

The biological activities of Epstein-Barr virus (EBV) from a human epithelial hybrid cell line derived from a nasopharyngeal carcinoma (NPC-KT) were studied. Low concentrations of virus from the NPC-KT cell line stimulated DNA synthesis of human cord blood lymphocytes (CBL) and induced CBL to form EBV nuclear antigen-positive continuous cell lines. The CBL exposed to higher doses of virus showed stimulated DNA synthesis 2 days after infection, followed by cell lysis. Virus from the NPC-KT cell line induced EBV-specific antigens in nonproducer Raji cells and reduced the colony-forming ability of the super-infected cells. The ratio of transforming activity to early antigen-inducing ability was not constant during cell passage. The data obtained suggest that NPC-KT clone 1 cells are producing virus with cytotoxic and transforming properties.

Superinfection of epithelial hybrid cells (D98/HR-1, NPC-KT, and A2L/AH) with Epstein-Barr virus and the relationship to the C3d receptor

Three Epstein-Barr virus (EBV) genome-positive epithelial/hybrid cell lines (D98/HR-1, NPC-KT, and A2L/AH) were superinfected with EBV derived from P3HR-1 (HR-1), NPC-KT, and B95-8 cells. The HR-1 virus is lytic and induces early antigen in superinfected Raji cells; the virus is not capable of transforming B-lymphocytes. Virus preparations from NPC-KT cells have both transforming and early antigen-inducing properties, while B95-8 virus can only transform B-lymphocytes. It was possible to demonstrate EBV antigens after superinfection of D98/HR-1 cells with both HR-1 virus and NPC-EBV. The NPC-KT hybrid cells, which were originally prepared by fusing human adenoid epithelial cells (Ad-AH) and EBV genome-positive NPC explanted epithelial cells, were susceptible to superinfection with HR-1 virus but not to NPC-EBV. The A2L/AH hybrid cells, which were prepared by fusion between Ad-AH cells and lymphocytes transformed by B95-8 virus, could not be superinfected with any of the virus preparations. In order to further investigate the nature of the EBV receptor as it relates to other cell membrane components, we examined cell surface markers on Ad-AH, NPC-KT, A2L/AH, and D98/HR-1 cells using monoclonal antibodies and by rosette formation. We found that the NPC-KT, A2L/AH, and Ad-AH cell lines express the OKB2 antigen and that the common acute lymphoblastic leukemia antigen is expressed on the A2L/AH cells. We also found that NPC-KT parental cells and a clone of NPC-KT cells express erythrocyte antibody complement b and erythrocyte antibody complement d, as determined by rosette formation, but were negative for C3b and C3d when monoclonal antibodies against these two markers were used. The D98/HR-1 cells were also confirmed to be negative for C3b and C3d. The data suggest that the C3d receptor may be part of the EBV receptor but that the C3d receptor, by itself, is not the only receptor to which EBV can bind.

Rescue of a biologically active Epstein-Barr virus from nonproducer cells

We recently established an epithelial/hybrid cell line, A2L/AH, by fusion of 8-azaguanine-resistant epithelial cells, Ad-AH, with a nonproducer lymphoblastoid cell line, A2L, using lymphocytes derived from the human nasopharynx transformed with the B95-8 strain of Epstein-Barr virus. The treatment of the parental A2L lymphoid cells with iododeoxyuridine led to the expression of Epstein-Barr virus early antigen, but neither virus capsid antigen or induction of Epstein-Barr virus DNA synthesis was observed. However, the treatment of the A2L/AH hybrid cells with iododeoxyuridine led to early antigen, virus capsid antigen and virus DNA synthesis, and the formation of virus particles. The virus rescued from the A2L/AH hybrid cells transforms human cord blood lymphocytes but is not able to induce early antigen in superinfected Raji cells.

Interaction of the antivirus agents remantadine and amantadine with lipid membranes and the influence on the curvature of human red cells

Surface potential difference, conductance, and elasticity changes of bilayer lipid membranes induced by the antivirus drugs amantadine and remantadine were measured. An influence on the human erythrocyte shape was shown. Both drugs are stomatocytogenic. The adsorption at the cytoplasmatic membrane was electrophoretically proved. The heat-induced vesiculation is partly inhibited. No microvesicles were observed. Instead, large tails which did not detach from the cell body were seen. The general conclusion is that these amphiphilic adamantane derivatives are membrane agents which modify membrane interaction processes, possibly by influencing the bending properties.

Rotation of dielectrics in a rotating electric high-frequency field. Model experiments and theoretical explanation of the rotation effect of living cells

Model experiments are carried out to clarify the mechanism of rotation of living cells in a rotating electric field. According to classical investigations of the rotation of macroscopic bodies in external fields, the rotation of spherical glass vessels or metal cylinder filled with electrolyte solutions was investigated. The relation of the calculations of Lertes (1921a,b) to the recent paper of Arnold and Zimmerman (1982) and our new derivations lead to equations explaining the rotation of objects. The results are compared with measurements using mesophyll protoplasts and data from the literature.

Modulation of cellular immunity in medical students

This study assessed the psychosocial modulation of cellular immunity in 34 medical-student volunteers. The first blood sample was obtained 1 month before examinations, and the second on the day of examinations. There were significant declines in the percentage of helper/inducer T-lymphocytes, in the helper/inducer-suppressor/cytotoxic-cell ratio, and in natural killer-cell activity in the blood samples obtained on the day of examinations. Half of the subjects were randomly assigned to a relaxation group which met between sample points; the frequency of relaxation practice was a significant predictor of the percentages of helper/inducer cells in the examination sample. Three biochemical nutritional assays (albumin, transferrin, and total iron-binding protein) were within normal limits on both samples. Data from the Brief Symptom Inventory showed significantly increased global self-rated distress associated with examinations in the no-intervention group, compared to nonsignificant change in the relaxation group. Clinical and theoretical implications are discussed.